Metering method and means



H .wkBEW 2 Shets-Sheet 1 J. H. RAMSER METERING METHOD AND MEANS July 10, 1951 Original Filed June 11, 1947 H i torn 03 M RZ n h J% fin mm 3 m NM m6 3 July 10, 1951 J. H. RAMSER 9 0 METERING METHOD AND MEANS Original Filed June 11, 1947 2 Sheets-Sheet 2 Figure 5 INVENTOR.

dahn H. Ramser my 5 KW/ Patented July 10, 1951 UNITED STATES METERING METHOD AND MEANS John H. Ramser, Chester, Pa., assignor to The Atlantic Refining Company, Philadelphia, Pa., a corporation of Pennsylvania Original application June 11, 1947, Serial No. 753,983. Divided and this application July 29, 1949, Serial No. 107,515

Claims. (Cl. 250-218) The present invention relates to improvements in method and apparatus adapted to determine the amount of entrained material in a fiuid, particularly to determine the amount of entrained solids in a gas, and more particularly to determine the amount of catalyst fines present in the flue gas from a regenerator of a fluid catalytic cracking unit.

This application is a division of my copending application, Serial No. 753,983, filed June 11, 1947, which is now U. S. Patent No. 2,498,506, granted February 21, 1950, and entitled Metering Method and Means.

In the operation of a fluid catalytic cracking unit, finely divided catalyst particles are injected into the fluid charge stream and, suspended therein, are carried to the reactor where, after their activity has been spent, such particles are caused to settle out and to returnto the regenerator. Hot air and steam blown through the regenerator remove coke or like matter deposited on the catalyst. As the hot air and steam are removed from the regenerator, such gases are passed through a cyclone separator and a precipitator to remove the catalyst particles remaining entrained therein. Although the greater part of the catalyst present in the gas is removed by such means there still remains a portion thereof suspended in said gas when it enters the flue leading from the precipitator. At the catalyst can be regenerated and used repeatedly, any loss thereof before it has become completely spent will increase the cost of the process being carried out. It is, therefore, of economic importance to keep the loss of catalyst at a minimum. Since the concentration of catalyst in the flue gas varies with operating conditions such as regenerator gas rate, water and ammonia content of the gas,

and other factors, it is desirable to know the exact concentration of catalyst in the fiue gas in order that such concentration can be held to a minimum by the control of such factors.

Heretofore, the concentration of catalyst fines in the flue gas of a fluid catalytic cracking unit has been determined by spot tests utilizing porous filters. This method is, however, subject to certain inherent defects, chief among them being the necessity for laborious calculations each time the test is run, possibility of error, and inability to determine the time variation of catalyst concentration in the gas unless frequent tests are run with a resulting increase in labor. Furthermore, it has, in the past, been impossible to determine the total amount of catalyst lost over any given period of time without resort to frequent tests and correlation of the results obtained thereby with the rate of gas flow such rate being obtained by divers other methods.

One of the objects of the invention, therefore, is to provide apparatus adapted for the instantaneous determination of the concentration of entrained solids in a gas, and more particularly for the instantaneous determination of the concentration of catalyst fines in the flue gas from a precipitator of a fluid catalytic cracking unit, which apparatus includes means for inhibiting the transfer of heat and vibration from the duct to the light source and the light sensitive element.

Another object of the invention is to provide means for adjusting the spatial relation between the light source and the light sensitive element.

Other objects of the invention will be apparent from the description and claims which follow.

The theory underlying the development of the present invention is that the actual concentration of catalyst fines at all points of a cross section of the flue gas stream in the stack is practically constant at any given instant of time even though the velocity of such gas stream may vary widely from point to point. If a beam of light of intensity Io is sent through the flue gas stream, the intensity of the transmitted light I is lower than 10 as a consequence of partial absorption and scattering of light by the catalyst particles in the flue gas. Since absorption and scattering of light by solid particles is independent of the state of motion of such particles, the intensity of the transmitted light is a function only of the concentration of the particles and the size thereof. Since the particle size varies only within narrow limits the relationship between transmitted light intensity and concentration can be determined for a given length of absorption path and given initial intensity of light; thus unknown concentrations may be instantly read or recorded by means of the intensity of the transmitted light.

In the drawing like numerals are used to designate like parts.

Figure 1 is a front elevational view exemplifying the apparatus partially in cross section.

Figure 2 is an enlarged top view partially in cross section taken along the line 2--2 in Figure 1.

Figure 3 is an enlarged cross sectional view of air injector ll shown in Figure 1.

In the drawing, t represents a duct or stack carrying the flue gas in which the finely divided catalyst is suspended. 'Pipe flange 5 is aflixed at an aperture 6 in the wall of duct 4 by welding or by other suitable means and has fastened thereto, as by bolts 1, or by other suitable means, apertured plate 8. Casing 9 extends through apertured plate 8 and is fastened thereto by welding or by other suitable means. Tube I0 is slidably disposed within casing 9 and projects beyond the inner end thereof adjacent aperture The outer end of easing 9 is externally flanged as at l3 and detachably affixed, as by bolts Hi, to flange 15 on pipe l6. Air injector I! provided with inlet [8, controlled by valve I9 is disposed around pipe IB. Passage of air from air injector ll into pipe [6 is permitted by holes 20 in said injector, tubes 2!, and openings 22 circumferentially spaced in the wall of pipe l6. Formed as an integral part of pipe is flexible metal bellows 23, the purpose of which will be discussed hereinafter.

Flange 24 on the outer end of pipe 16 is aflixed, as by bolts 25, to flange 26 on light source pipe 2'1. Positioned between flange 24 and flange 26 and adapted to blank off light source pipe 21 from pipe I6 when so desired is figure eight flange 28.

Detachably affixed to the outer end of light source pipe 2! is light source housing 29 having positioned internally thereof window 39 capable of transmitting light but preventing admission of air from light source pipe 21. Also p ovided within light source housing 23 are light source 3|, such as, for example, a tungsten filament lamp or the like, and parabolic mirror 32 aflixed to housing 29 as at 33.

For purposes of support, column 34 is provided. Plate 35 on top of such column and aflixed thereto by angle irons such as 36 bears slidabl bracket 31 which, by means of bolt 38, is removably attached to fin 3S welded, or fastened by other suitable means, to light source pipe 21. Further support for light source housing 29 is provided by L shaped support 45! detachably affixed to the underside of such housing by bolt 5i, such support extending downward through plate 35 and being aflixed to angle iron 42, by any suitable means which will permit either vertical or horizontal movement of housing 219, if desired.

Pipe flange 43 is aflixed at aperture 44 in the wall of duct 4 by welding or by other suitable means, and has fastened thereto, as by bolts 45, or other suitable means, apertured plate 46. It will be apparent by reference to the drawing, particularly Figures 1 and 2 that aperture 44 is formed in the Wall of duct 4 at a diametrically opposed point to aperture 6 so that pipes 9 and 41 are coaxially arranged. Casing 47 extends through apertured plate .5 and is fastened thereto by welding or other suitable means. Tube 48 is slidably disposed within casing 41 and projects beyond the inner end thereof adjacent aperture 44 in duct 4. Handles 49 and 56 slidably extend through apertured plate 45 and are aflixed to tube 48, the purpose of tube 48 and handles 49 and 58 being more fully discussed hereinafter.

The outer end of easing ll is externally flanged as at 5! and detachably ainxed, as by bolts 52, to flange 53 on pipe E l. Air injector 55, provided with inlet 56 controlled by valve 5'! is disposed around pipe 54. Air injector 55 is, in all respects, identical with air injector i? shown in detail in Figure 3. Formed as an integral part of pipe 54 is flexible metal bellows 58, the purpose of which will be discussed hereinafter.

External flange 59 on the outer end of pipe 54 is aifixed, as by bolts 60, to flange 6| on light receiving pipe 62. Positioned between flange 59 and flange 6i and adapted to blank off light receiving pipe 62 when so desired is figure eight flange $3.

Detachably affixed to the outer end of light receiving pipe 62 is light sensitive element housing 64 having positioned internally thereof pianoconvex lens 65 effectually preventing the admission of air from light receiving pipe 62 but per- 4 mitting the passage of light. Light sensitive element 66, such as a thermopile, or the like, is positioned within light sensitive element housing 64 and is connected by wires Bl and 68 to output meter 69, such as, for example, a millivolt potentiometer or the like.

For purposes of support, column in is provided. Plate ll on top of such column and afiixed thereto by angle irons i2 bears slidable bracket 73 which, by means of bolt 74., is removably attached to fin 15 welded, or fastened by other suitable means, to light receiving pipe 52. Further support for light sensitive element housing 5-! is provided by L shaped support '56 detachably amxed to the underside of such housing by bolt ll, the support extending downward through plate H and being aflixed to angle iron 18 by any suitable means which will permit either horizontal or vertical movement of housing 54, if desired.

It will readily be understood that, While the device described above presents a preferred embodiment of the invention, certain variations can be made without departing from the scope of the appended claims. For example, although a tungsten filament lamp, a thermopile, and a millivolt potentiometer have been specified as light source 35, light sensitive element 66, and output meter 55, respectively, any combination reaching a similar result can be used. Among such other combinations that might suggest themselves to those conversant with the art are a mercury arc lamp, a photocell of the barrier layer type, and a microammeter; or a sodium vapor lamp, a photoelectric tube, and an amplifier connected to a suitable current or voltage measuring device.

The operation of the device is as follows:

As the flue gas carrying an unknown concentration of catalyst passes through duct 4, a light beam of constant intensity emitted by light source 3! and reflected in parallel rays by parabolic mirror 32 emerges from light source housing 29 through window 3% into light source pipe 21, passes through pipe it and tube it and thence enters duct 4. The light beam traverses the known (iiameter of duct i, enters slidable tube 58 positioned within casing ll and passes through pipe 54 into light receiving pipe 62. The total transmitted light is focused by plane-convex lens 65 upon light sensitive element 56 in light sensitive element housing 64. The electromotive force generated by the impact of such light beam upon light sensitive element 68 is indicated by output meter 59. Since the intensity of transmitted light as a function of catalyst concentration has been determined by previous experimentation, the instantaneous concentration of catalyst in the flue gas may be determined by converting the reading of output meter 69 into concentration by use of a calibration curve or other suitable means. If so desired, output meter 69 can be calibrated directly in terms of catalyst concentration.

In order to record accurately the concentration of catalyst in the flue gas, the intensity of the light beam must be kept constant at all times. Air injectors H and 55 are adapted to achieve this end. The injection of air into pipe 16 and pipe 54 through the respective injectors gives rise to a pressure in such pipes which is positive in relation to the pressure in duct 4 and results in a smooth, uniform flow of air from said pipes into said duct. Such being the case, the accumulation of catalyst particles or moisture in the light path or on window 39 and plane-convex lens 65 will be inhibited.

The intensity of the light beam for a zero concentration of catalyst (upon which intensity all other calculations are based) can be determined without interfering with the flow of flue gas through duct 4. By means of handles 5 i and i2, tube H3 slidably positioned within casing 9, is advanced into duct A. Similarly tube 48 slidably positioned within casing All is advanced by handles 69 and 53 until a junction is made with tube is, thereby providing a passage, substantially free of catalyst particles through which light beam can pass. A reading can then be obtained on output meter 29 and compared with the original reading for a zero concentration of catalyst. If the readings do not coincide the intensity of the light beam is readjusted to its original value by varying the intensity of light source 3!. Once said original reading has been obtained, the slidable tubes are retracted to their inoperative positions within casings 9 and 4'5 respectively. It is apparent that, instead of two slidable tubes such as iii and 48, one tube can be used if of suincient length to span the entire diameter of duct 4.

It has been found that, after an extended period of operation, the reading for zero concentration of catalyst is less than the original reading, due to the slow accumulation of catalyst on window 30 and plano-convex lens 85. As a result, it is necessary to clean window 3%} and plano-convex lens 6'5. In such case figure eight flanges 28 and 63 are turned until the blank portions thereof are seated between light source pipe 2'! and pipe ii, and light receiving pipe 62 and pipe E i respectively, thus blanking off light source pipe 2? and light receiving pipe 85 from duct 2. Thus, window 3i) and plano-convex lens 65 can be removed from light source housing 28 and light sensitive element housing 54, respectively, without halting normal operation of duct 4 or permit ing flue gas or catalyst particles to enter the respective hous ings.

The accurate adjustment of the apparatus to provide a continuous path from light source 3! to light sensitive element 66 can be readily accomplished by virtue of slidable brackets 31 and l affixed to light source pipe 2? and light receiving pipe 62, respectively. By raising or lowering light source housing 29 and light sensitive element housing 64 with respect to brackets 37 and respectively, and adjusting bolt 38 with respect to bracket 37 and bolt 7:1 with respect to bracket 73, a path through which the light beam can pass with no obstruction other than the entrained catalyst is obtained. Furthermore, such adjust ment can also be obtained by moving housing 2e and support to relative to angle iron i2, and housing 5 1 and support 75 relative to angle iron 78.

Bellows 23 and 5'8 on pipes 55 and 5d, respectively, are adapted to minimize the transfer of vibration and heat from duct 4 to the more sensitive parts of the device, namely, light source 35 and light sensitive element 55 by reason of their flexibility, thinness of wall, and large surface area.

The examples here given and the particular description set forth are presented in order to illustrate how the invention may be applied. Other forms and variations coming within the scope of the appended claims will readily suggest themselves to those skilled in the art.

I claim:

1. Apparatus for determining the concentration of entrained solids in a gas, which comprises a duct having opposed openings in the walls thereof, pipes associated with said duct and communicating with said openings, a light source positioned within one of said pipes, a light sensitive element positioned within the other of said pipes, and means attached to said pipe for inhibiting the transfer of heat and vibration from said duct to light source and said light sensitive element.

2. Apparatus for determining the concentration of entrained solids in a gas, which comprises a duct having opposed openings in the walls thereof, pipes associated with said duct and communicating with said openings, a light source positioned within one of said pipes, a light sensitive element positioned within the other of said pipes, and means inhibiting the transfer of heat and vibration from said duct to said light source and said light sensitive element, said inhibiting means consisting of flexible bellows disposed in said pipes.

3. Apparatus for determining the concentration of entrained solids in a gas, which comprises a duct having opposed openings in the walls thereof, pipes associated with said duct and communicating with said openings, a light source positioned within one of said pipes, a light sensitive element positioned within the other of said pipes, and means inhibiting the transfer of heat and vibration from said duct to said light source and said light sensitive element, said inhibiting means consisting of flexible bellows attached to said pipes.

4. In apparatus for determining the concentration of entrained solids in a gas which comprises a duct having opposed openings in the walls thereof, pipes associated with said openings, a light source positioned within one of said pipes, and a light sensitive element posiioned within the other of said pipes, means for adjusting the spatial relation between said light source and said light sensitive element, including flexible bellows disposed, in said pipes, supporting members associated with said pipes, and slidable brackets affixed to said supporting members and adapted to be detachably affixed to said pipes.

5. In apparatus for determining the concentration of entrained solids in a gas which comprises a duct having opposed openings in the walls thereof, pipes associated with said openings, a light source positioned within one of said pipes, and a light sensitive element positioned within the other of said pipes, means for adjusting the spatial relation between said light source and said light sensitive element, including flexible bellows attached to said pipes, supporting members associated with said pipes, and slidable brackets affixed to said supporting members and adapted to be detachably afiixed to said pipes.

JOHN H. RAMSER.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 1,508,004 Bancel Sept. 9, 1924 1,785,392 Sawford et a1. Dec. 16, 1930 1.991570 Vedder et a1. Mar. 14, 1933 2,244,507 Thomas June 3, 1941 2,291,776 Wager Aug. 4, 1942 2,434,924 Hamilton Jan. 27, 1948 

